expression, noun-modifying (irregular)
uninteresting; dull; straightforward
Describes a person, story, or thing that lacks twists, quirks, or peculiarities; often used in the phrase 曲のない人 for a straightforward, uncomplicated person.
He's a straightforward person and quickly gets along with anyone.
この小説は曲のない展開で、すぐに結末が読めてしまう。
This novel has a predictable plot, and you can guess the ending right away.
Standard spelling; the kanji 曲 here means 'twist' or 'peculiarity', not 'song'.
Alternate spelling using 無い for ない; slightly more formal or emphatic.
From 曲 (きょく, 'twist, peculiarity') + の (possessive particle) + ない ('not exist'). Literally 'without twists', extended to mean 'uninteresting' or 'straightforward'.